In the prior art, the use of aluminum alloys in heat exchanger applications is well known. Aluminum alloys are used for heat exchanger headers, tubing, fins and connector blocks. Typically, the connector blocks are brazed to the header to facilitate the hookup of fluid supply and takeaway lines of a system requiring fluid cooling, e.g., an air conditioning system.
When manufacturing the heat exchanger assemblies, the components are often clamped together and furnace brazed using either clad materials, filler brazing materials or a combination of both.
One significant problem that occurs during the manufacturing of the assembly is the formation of an inferior brazing joint between the connector block and the heat exchanger header. Prior to brazing, the connector blocks are often machined and combined with fasteners to facilitate connection to the fluid supply or takeaway lines. Because of the physical property requirements associated with the machining and the fastener use, prior art connector blocks are usually made from AA6000 series aluminum alloys. These types of aluminum alloys exhibit poor machinability and are not easily brazed by the CAB brazing process due to their high magnesium content. Consequently, it is often difficult to obtain a high quality brazed joint between the connector block and another component of a heat exchanger assembly. Utilizing a more brazeable alloy such as a standard or commercial AA3000 series alloy does not present an acceptable alternative as a material for connector block use. The AA3000series alloys, while being brazeable, are generally too soft to adequately machine or have the necessary mechanical properties to facilitate mechanically fastening the connector block to other components.
As such, a need has developed to provide an improved connector block for heat exchanger application. In response to this need, the present invention provides an improved aluminum alloy article or connector block which combines both machinability and brazeability. The inventive aluminum alloy article also has mechanical properties making it suitable for use as a heat exchanger connector block and has adequate corrosion resistance. The aluminum alloy article also facilitates the brazing process when assembling the heat exchanger components together.